1. Field of the Invention
The present invention relates to a sealing device for a joint such as a tripod joint or Birfield joint for automobiles which comprises a first shaft, rotary means arranged around an end portion of the first shaft, a casing receiving the rotary means through one end and provided with a flange on the periphery of the other end thereof, and a second shaft provided with a flange at one end thereof to be connected to the flange of the casing, and more particularly to a sealing device disposed between the flanges.
2. Description of the Prior Art
In a joint of the type as mentioned in the above, it is common that a grease is enclosed in the casing for lubricating the rotary means. In order to prevent leakage of the grease, it is common to place a rubber boot between the opening end of the casing and the first shaft which extends through the opening end, and to insert a rubber packing between the joined flanges.
The essential function of such a joint is to transmit a driving power from the first shaft via the casing to the second shaft or inversely from the second shaft to the first shaft. If a rubber packing is inserted between the joined flanges, this essential function of transmitting a driving power can not satisfactorily be performed because of the resiliency of the rubber packing. In order to overcome this difficulty, a system has been proposed and practically in use, wherein an end cover is placed as a blind plate between the flanges so that the periphery of the end cover is held between the flanges and the packing is held between a portion of the end cover inside of the periphery and the flange of the casing.
However, in such a conventional system, there are certain problems at the time of assembling. Namely, in order to avoid dislocation of the packing, it is necessary to fix the position of the packing at the time of assembling. However, there has been no satisfactory method available which is capable of efficiently and precisely positioning the packing. For instance, it is conceivable to paste up the packing on the end cover. However, it is not necessarily easy to paste up the packing uniformly. It is likely that some portions are not properly stuck while other portions are stuck. Even when the packing is entirely adhered to the end cover, if there exists an irregularity in the distribution of the amount of the adhesive, it is possible that the sealing becomes defective. Further, the work involved in such a pasting-up operation adds to the costs.
Further, upon completion of the assembling, the packing is not visible from outside the joint, and it is therefore impossible to ascertain whether the packing is properly located at the predetermined position.